diff -r b0022324fb4e -r d2b58cf339fe QTfrontend/model/ThemeModel.cpp
--- a/QTfrontend/model/ThemeModel.cpp	Sun Mar 18 15:24:54 2018 +0100
+++ b/QTfrontend/model/ThemeModel.cpp	Sun Mar 18 15:42:17 2018 +0100
@@ -131,7 +131,7 @@
             dataset.insert(IsHiddenRole, true);
 
         // detect if theme is dlc
-        QString themeDir = PHYSFS_getRealDir(QString("Themes/%1/icon.png").arg(theme).toLocal8Bit().data());
+        QString themeDir = PHYSFS_getRealDir(QString("Themes/%1").arg(theme).toLocal8Bit().data());
         bool isDLC = !themeDir.startsWith(datadir->absolutePath());
         dataset.insert(IsDlcRole, isDLC);